Information Retrieval is an area of study concerning with retrieving documents, information or metadata from a collection of unstructured or semi-structured data.

Information Retrieval is an area of study concerned with retrieving documents, information or metadata from a collection of unstructured or semi-structured data.

It usually has 3 parts:

  1. Crawling: Identifying the documents that we want to search when our document collection is not clearly defined, especially important to web search engines.
  2. Indexing: Parsing and inverting the documents into an index, either a static offline process or a set of incremental updates for frequently changing document collections.
  3. Searching: retrieving the most relevant documents to the given query. This step requires that we rank documents with scoring functions which measure how relevant the documents are to each query.